The present invention relates in general to a memory system, and in particular to a memory system having improved routability.
A memory module is a memory device used by modern computer systems to provide a system memory or workspace for processors to execute programs. The system memory is in essence, a staging area between a large fixed storage medium such as a hard drive, and the central processing unit. Data and programs are loaded into and out of the system memory as needed by the computer.
The demands for more memory and greater access speed are continually increasing in modern computer systems. However, the basic motherboard architecture, among other factors, limits the number of memory slots in which memory modules may be placed. The memory manufacturer is thus faced with the challenge of providing greater capacity and speed on each memory module. Surface mount technology (SMT) and double sided surface mount technology have allowed memory manufacturers to increase the number of integrated circuit chips placed on each memory module. However, the number of lead traces on the memory module required to interconnect the chips increases as the number of integrated circuit chips increase. Additionally, increasing the storage capacity of each memory chip requires additional external pin connections per memory chip to account for the additional data and address bus widths. These increases further add to the number of lead traces required on a memory module. As circuit speed increases, the distributed capacitance and inductance over the length of each lead trace on a memory module causes it to act like a transmission line. Further, crosstalk may become a limiting factor to memory performance due to mutual inductance or capacitance, and can cause a loss of signal strength in the active line.